Presently, disposable trays, including cat litter trays, fall into two main types. Trays of the first type have outwardly slanted walls, i.e., their side walls are oriented at an angle of less than 90 degrees (typically from 60 to 80 degrees) relative to the plane on which the tray is placed. These trays make it possible to stack them in a nested configuration and thus minimize the occupied shelf space/volume per tray. This feature (known as nested stackability) is desirable to the retailer of disposable trays as well as to the consumer who buys more than one tray at a time. A prior art example of this type of trays is disclosed in U.S. Pat. No. 4,716,853 (Jan. 5, 1988), issued to d'Aniello, and is herein incorporated, by reference, in its entirety. Typically, these trays are made of plastic material and often are thermoformed from plastic material sheets. Also, in some configurations, as disclosed in U.S. Pat. No. 4,716,853, they are designed to include a bottom cavity (or a recessed bottom) filled with liquid-absorbent litter granules and covered with a removable paper sheet or plastic film liner. An advantage of trays of this type is that, as purchased, they are ready to use and no assembly is required. However, trays of this type are also very difficult to fold and thus are not folded, as sold as well as after being used. They are also difficult to fit in a trash collection barrel. Furthermore, when the consumer attempts to fold them in order to dispose of them, the litter granules accumulate and heap in the lateral middle line zone of the tray and spill out of the tray, over the long side walls of the tray. For the purpose of this disclosure, the lateral middle line zone of a rectangular tray is defined as the area immediately adjacent to and surrounding the lateral axis of symmetry of the tray; wherein the lateral axis of symmetry of the tray is perpendicular to the long side of the rectangular tray.
Trays of the second type have vertical side walls, i.e., their side walls are oriented at an angle of 90 degrees relative to the plane on which the tray is placed. They are usually made of cardboard sheets suitably die cut and scored to form vertical side walls folded or foldable trays and boxes. As compared to trays of the first type, a disadvantage of trays of this type is that, in their ready to use configuration, they occupy a much larger shelf space per unit. An improved tray of this type is disclosed in U.S. Pat. No. 7,255,261 (Aug. 14, 2007), issued to Mesly, and is herein incorporated, by reference, in its entirety. As disclosed therein, Mesly teaches a vertical wall type tray having three configurations, a flat folded (as offered for sale) configuration, an assembled (presumably by the consumer) vertical walls configuration and a folded (ready for disposal) configuration.
Other prior art patents disclose cat litter trays and boxes; for example U.S. Pat. Nos. 5,035,205, 6,382,131, 6,676,010, and 5,205,476, each of which is herein incorporated, by reference, in its entirety.
All currently available, as well as disclosed in the prior art, disposable cat litter trays suffer from the problem of litter granules accumulating and heaping in their lateral middle line zone and across the entire width of the tray when the consumer attempts to fold them in order to dispose of them. Often, litter granules spill out of the tray, over the long side walls of the tray.